A nut of this kind is known from U.S. 2009/0226281 A1, for example. In the known nut, threaded partial segments which extend over a portion of the circumference are accommodated in the first part, the threaded partial segments being movable, in particular vertically movable, relative to the first part. A second part forms a counterstop for a compression spring which acts on the threaded partial segments. The known nut may be mounted on a threaded bolt, the receding threaded partial segments allowing the nut to slide over the thread. When the nut is then rotated, the threaded partial segments engage in the thread of the bolt, and the nut may be tightened. A washer which is also provided and is connected to the first part in a rotatable manner and also connected to a spring chamber that is fixed to the nut in a positive-fit manner, creates continuous preloading of the nut in the locking direction due to biasing of the spring when the nut is tightened and the washer rests on an item to be loaded, so that loosening is counteracted.
Nuts of this kind and combinations of nuts with bolt parts are in addition known from U.S. Pat. No. 4,781,507 B1 and GB 692041 B. In the case of the item from the US specification mentioned, two nut parts are provided that have thread turns and are freely rotatable relative to one another. Furthermore, an insertion part having no profile is provided which is rotatable relative to the threaded parts mentioned. It is possible for the rotatability of the part formed without profiling relative to a threaded part to be unlimited. The twisted position can only be secured between the parts that have the thread formations.
The bolt to be introduced into the nut is provided with a thread formation right up to its free end.
A nut is known from the British specification mentioned in which a part can be inserted that can be decent-locked on this nut in rotationally delimited manner and has an opening which is formed without a profile and through which a bolt can be inserted. In addition, a threaded part which furthermore also has an external thread can be screwed into the nut. For release, the parts can only be unscrewed together.
Nut securing systems are also known in other configurations. Reference is made to DE 197 01 317 B4, EP 2 128 461 A1, DE 198 25 132 A1, and FR 2 762 367 A1, for example.